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Comment by fc417fc802

25 days ago

Why should I need a separate device? Doesn't a hardware security token suffice? I wouldn't even mind bringing my own but my bank doesn't accept them last I checked. (Do any of them?)

If the bank can't be bothered to either implement support for U2F or else clearly articulate why U2F isn't sufficient then they don't have a valid position. Anything else they say on the matter should be disregarded.

You shouldn't need a separate device, but we are quickly entering an era where a lot of banking (and other) apps will outright refuse to run or allow logins if it detects a rooted device, or play integrity fails.

In this way, the banks are asserting control over your device. It's beyond authentication, they are saying "If you have full control over your device, you cannot access our services."

I'll agree with you that they don't have a valid position, because I can just as easily open up a web browser on said rooted device and access just fine via the web, but how long until services move away from web interfaces in favor of apps instead to assert more control?

  • I have to use my phone to approve the web login to my account. My bank is working very hard to make sure that everyone uses the app for everything, including closing down offices and removing ATMs around the city.

A hardware token would not suffice. When you login with a hardware token it will generate some sort of token or cookie for further requests. This is where malware can steal that key and use it for whatever it wants. There is a benefit it knowing there is a high chance that the such a key is protected by the operating system's sandboxing technology. Without remote attestation you don't know if the sandbox is actually active or not.

  • On the contrary, a hardware token will suffice to thwart both phising and MitM which covers ~everything for all practical threat and liability models. What exactly is the concern here? A widespread worm that no one is yet aware of that's dumping people's bank accounts into crypto? It might make for a decent Hollywood plot but is pulling that off actually easier than attacking the bank directly?

    Keep in mind that the businesses pushing this stuff still don't support U2F by and large. When I can go down in person to enroll a hardware token I might maybe consider listening to what they have to say on the subject. Maybe. (But probably not.)

    • Hypothetically on a fully controlled system you could prevent attacks like the sort of “hello this is Microsoft, we’ve identified a virus on your device, please download teamviewer and login to your bank account so we can clear it for you” type spam calls.

      Or, hasn’t there been malware that periodically takes screenshots of the device? Or maybe that’s a Hollywood plot, I forget actually.

      3 replies →

    • How does it solve MITM? You type your hardware token in and then an attacker uses it to send money out of your account.

      >What exactly is the concern here?

      Stealer malware. Or even RATs where attackers get notified when you open a sensitive app and they can take over after you have authenticated.

      4 replies →